Endoprosthesis for the treatment of blood-vessel bifurcation stenosis and purpose-built installation device

ABSTRACT

An endoprosthesis for the treatment of blood vessel bifurcation stenosis. The endoprosthesis comprises three tubular sections and two connections. A distal section is aligned at least approximately with a proximal section. The first distal section is intended for insertion into a first blood vessel branching off on the bifurcation. The first distal section is linked to the proximal section by a first lateral connector. A second distal section, located at the side of the first distal section, is intended for insertion into a second vessel branching off from bifurcation. The two distal sections have their proximal ends linked by a second connector.

This is a divisional application of Ser. No. 08/945,973 filed Jan.26,1998, now U.S. Pat. No. 6,183,509.

This invention relates to the field of endoprostheses for the treatmentof blood-vessel bifurcation stenosis.

This invention also relates to a purpose-built installation device.

BACKGROUND

It has already been suggested that stenosis found in coronary arteriesbe treated using endoprostheses formed from tubular structuresperforated With a grid pattern of slits and consequently expandablefollowing placement at the site of stenosis. In most cases theseendoprostheses are expanded by inflating a balloon which is placedinside them and subsequently withdrawn.

Generally speaking, endoprostheses of this type may be said to havealready given good service.

They are not, however, fully satisfactory.

The applicant has, in particular, observed that standard endoprosthesesare not fully satisfactory when, as is frequently the case, there isstenosis at a blood-vessel bifurcation. In such cases, treatment usingstandard endoprostheses requires two separate endoprostheses. One ofthese is placed in each of the two vessels branching off from thebifurcation and their positioning in relation to each other is adjustedas finely as possible to ensure optimal cover of the bifurcation area.

A primary goal of this invention is to develop existing endoprosthesesin order to facilitate and improve treatment of blood-vessel bifurcationstenosis.

This goal is attained by this invention through the use of anendoprosthesis comprising three tubular sections and two connectors,namely:

a proximal section;

a first distal section aligned at least approximately with the proximalsection and intended for insertion into one of the vessels branching offfrom the bifurcation, this distal section being attached to the proximalsection by means of a laterally positioned connector; and

a second distal section placed at the side of the first distal sectionand intended for insertion into the second vessel branching off from thebifurcation, the two distal sections having their proximal ends joinedby the second connector.

In accordance with another advantageous feature of this invention, thedistal end of the proximal section is chamfered and the proximal end ofthe second distal section is tapered at the other side of the secondconnector and fits into the chamfer in the proximal section.

The above-mentioned chamfered shapes and tapered ends may have a varietyof embodiments. They may, in particular, be delimited by flat or curvedsurfaces.

Another important goal of this invention is to perfect the method ofinstalling the above-mentioned endoprostheses.

According to this invention this goal is attained by using adouble-balloon system, as follows:

a first balloon of suitable length for insertion into two approximatelyaligned sections of the blood vessel to be treated: the main stem andthe first branching blood vessel, on either side of the bifurcation arearespectively; and

a second balloon of suitable nature for insertion into the second bloodvessel branching off from the bifurcation.

In accordance with another advantageous feature of the invention, thefirst balloon incorporates a lateral recess to be positioned facing thebifurcation area with a view to housing the proximal end of the secondballoon.

In accordance with another advantageous feature of this invention, thedistal portion of the first balloon located downstream of the recess isof smaller diameter than the proximal portion of the balloon locatedupstream of the recess.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, goals and advantages of the invention will be apparenton reading the following detailed description as illustrated in thecorresponding accompanying drawings, which are given as non-exhaustiveexamples and in which:

FIG. 1 is a schematic side view of an endoprosthesis in accordance withthis invention;

FIG. 2 is a perspective view of the same endoprosthesis;

FIG. 3 is another perspective view of the same endoprosthesis afterrelative inclination of the distal sections;

FIG. 4 is a view of the same endoprosthesis following expansion of thevarious tubular sections from which it is formed;

FIG. 5 is a schematic illustration of an endoprosthesis combined withthe device for installing it, prior to implantation in astenosis-affected bifurcation area;

FIG. 6 is a view of the same instrument following implantation in abifurcation and expansion of the proximal section and one distalsection;

FIG. 7 is a view of the same endoprosthesis after expansion of the threesections from which it is formed;

FIG. 8 is a schematic side view of the first balloon in accordance withthe invention;

FIG. 9 is a side view of the second balloon in accordance with theinvention;

FIG. 10 is an overall view of an installation instrument comprising twoballoons working together in accordance with the invention;

FIG. 11 is another side view of the balloon-based installation system inaccordance with the invention;

FIG. 12 is an overall view of the same balloon-based installation toolcombined with means of inflation; and

FIG. 13 is a schematic cross-sectional view of a feeder tube for thedouble-balloon system.

DETAILED DESCRIPTION

The first item described will be the structure of endoprosthesis 100 inaccordance with the invention and illustrated in FIGS. 1 to 7. As wasmentioned earlier, endoprosthesis 100 comprises three tubular sections(110, 120 and 140) and two connectors (130 and 150).

The first section (110) is a proximal section having as its centre axis111. It is intended for insertion into main stem T1 of blood vessel Vfor treatment, upstream of the bifurcation.

The first distal section (120) having as its section axis 121 is atleast approximately aligned with proximal section 110 prior to use. Thisfirst distal section 120 is intended for insertion into blood vessel T2branching off from the bifurcation as is seen in particular in FIGS. 6and 7.

The first distal section (120) is attached to proximal section 110 bythe first lateral connector (130).

The second distal section (140), having as its axis 141, is positionedat the side of the first distal section (120), and has the advantage ofbeing parallel to the latter, prior to use. The second distal section(140) is intended to be inserted into blood vessel T3 branching off fromthe bifurcation, as is seen in particular in FIGS. 6 and 7.

The two distal sections 120 and 140 have their proximal ends (122 and142) linked by the second connector (150).

Each of section 110, 120 and 140 is preferably formed from a tubularcomponent perforated with a grid pattern of slits such that thestructure of sections 110, 120 and 140 allows them to expand along theircircumferences.

In practice, section 110, 120 and 140 of endoprosthesis 100 can bemanufactured from extruded cylindrical parts made of a bendable metalalloy such as 316L stainless steel. The external diameter of section of110, 120 and 140 typically ranges from 1 to 1.2 mm prior to use:

There can be a range of variants of the grid pattern cut into sections110, 120 and 140. The opening may take the form of a hexagon or diamond,as shown in the accompanying figures, taking on the appearance ofgrating following, expansion against the inner surface of the coronaryartery by means of a cylindrical balloon placed inside.

As the basic structure of expandable tubular components 110, 120 and 140and the material from which they are made are familiar to those skilledin the art, these particulars will not be described in detail in whatfollows.

The three sections 110, 120 and 140 are preferably of equal diameterprior to expansion, i.e. prior to use.

The respective axes (111, 121 and 141) of sections 110, 120 and 140 arecoplanar and determine a plane of symmetry for the endoprosthesis. Thisplane of symmetry is parallel to the plane of FIG. 1.

The first connector (130) has as its centre the above-mentioned plane ofsymmetry determined by axes 111, 121 and 141.

Connector 130 links an area of distal end 113 of proximal section 110with an area of proximal end 122 of the first distal section (120). Yetmore specifically, articulation 130 preferably consists of a strip ofconstant width parallel to axes 111 and 121. Articulation 130 isdiametrically opposite the second distal section (140) with respect toaxes 111 and 121.

Distal end 113 of proximal section 110 is provided with chamfer 115 inits peripheral area situated opposite connector 130. Chamfer 115 can bedetermined by a plane that is inclined with respect to axis 111,perpendicular to the above-mentioned plane of symmetry or, again, becurved, for instance, concave with respect to distal section 120.Angular opening of the wall of proximal section 110 thus increasesstarting from connector 130 and turns through 360,°i.e. a completetubular form around axis 111.

This cant (115) forms a type of arch located on the side oppositeconnector 130 embodying in the cylindrical structure forming proximalsection 110 the shape of the ostium of the blood vessel branching offfrom the coronary bifurcation onto which it will be applied.

Furthermore, proximal end 142 of the second distal section (140) istapered at the other side of the second connector (150). It stretchesforwards in its peripheral area opposite the second connector (150).This tapered portion (144) may also be determined by a plane that isinclined with reference to axis 121, perpendicular to the plane ofsymmetry or, again, by a curved surface.

After expansion, as is illustrated in FIG. 4 for example, when theendoprosthesis is installed at the bifurcation of the two coronaryarteries, distal portion 113 with the corner cut off (115) of proximalsection 110 is fixed together harmoniously with the proximal (114) ofsection 140 of the endoprosthesis and ensures maximum coverage of thedilated coronary bifurcation area.

In this way, once in place, the whole of the grid of the bifurcatedendoprosthesis (100) covers the proximal and distal portions of the twocoronary branching arteries and the whole of the dilated bifurcationarea.

The first connector (130) preferably forms an integral part, i.e. it isnot joined onto sections 110 and 120.

In other words, the first connector (130) and sections 110 and 120 arepreferably manufactured from a single part in which connector 130 isformed via machining.

The second connector (150) is also centred with reference to the planeof symmetry determined by axes 111, 121 and 141.

However, whereas the first connector (130) extends in a direction thatis parallel to axes 111 and 121, the second connector (150) extends in adirection that is transversal to the above-mentioned axes 111, 121 and141 and links adjacent areas of proximal ends 122 and 142 of distalsections 120 and 140.

The second connector (150) is preferably joined to proximal ends 122 and142 or sections 120 and 140 by means of, for example, laser welding.

This aspect of the invention can, naturally, be embodied by a range ofvariants in that the second connector (150) could form an integral partwith distal sections 120 and 140 formed from a single part whileconnector 130 would be joined by means of, for example, laser welding tothe distal end of proximal section 110 and the proximal end of distalsection 120.

In accordance with a particular embodiment, given as a non-exhaustiveexample, bifurcated endoprosthesis 100 for the coronary arteryconforming with this invention has the following dimensions:

the total length of endoprosthesis 100 measured from proximal end 112 ofproximal section 110 to distal end 123 of distal section 120 is of theorder of 15 mm;

the diameter of sections 110, 120 and 140 is of the order of 1 mm priorto expansion;

the length of proximal section 110 is of the order of 7.5 mm prior toexpansion;

the length of distal section 120 is of the order of 7 mm prior toexpansion;

the length of distal section 140 is of the order of 9 mm prior toexpansion;

the length of connector 130 is of the order of 0.5 to 1 mm; and

the diameter of distal sections 120 and 140 in their expanded state isof the order of 3 mm while the diameter of proximal section 110 is ofthe order of 3.5 mm.

A description now follows of the structure of the instrument fitted witha double asymmetric balloon conforming with this invention which isshown in FIG. 8 et seqq.

Essentially, this instrument (200) comprises two balloons (210 and 230).The first balloon (210) is of a length consonant with its purpose ofbeing positioned inside two approximately aligned sections (T1 and T2)of vessel V for treatment: main stem T1 and a branching vessel T2,situated one on either side of the bifurcation area respectively, or,again, of being positioned inside proximal section 110 and distalsection 120 of endoprosthesis 100.

As regards the second balloon (230), this is consonant with its purposeof being positioned in the second blood vessel (T3) branching off fromthe bifurcation. Balloon 230 is preferably shorter than balloon 210. Asshown in the accompanying figures, the two balloons 210 and 230 arepreferably formed from generally cylindrical elongated tubular itemscentred upon axes 212 and 232 and having their ends (214 and 216; 234and 236) more or less rounded.

The main balloon (210) preferably incorporates a recess in its side(218) suitable for housing proximal end 236 of the second balloon (230)as shown in FIG. 10.

Furthermore, proximal portion 219 of balloon 210 located upstream ofrecess 218 is preferably of greater diameter than distal portion 217 ofthe same balloon located downstream of recess 218.

Each of the balloons 210 and 230 is preferably fitted With aradio-opaque tracer (220 and 240). Tracers 220 and 240 are preferablylocated at the centres of their respective balloons 210 and 230. Tracers220 and 240 may, for example, be carried by hollow internal tubes 221and 241 housing metallic guides 222 and 242 having as their centres axes212 and 232 and passing axially through balloons 210 and 230respectively. Tracers 220 and 240 are preferably located halfway alongballoons 210 and 230.

Balloons 210 and 230 are prolonged at their proximal ends 216 and 236by, respectively, tubes 224 and 244, of narrow cross-section, designedto feed and, consequently, dilate balloons 210 and 230.

Tubes 224 and 244 preferably house guides 222 and 242. Morespecifically, each of the two tubes 224 and 244 preferably has twolumina: the first lumen houses a guide (222 and 242) and opens into theassociated internal tube (221 and 241) and the second lumen, used forinflating the balloons, opens into the inside surface of the balloons(210 and 230).

The above-mentioned internal tubes 221 and 241 and first lumina are notconnected with the internal surface of balloons 210 and 230.

Furthermore, internal tube 221 inside the first balloon (210) ispreferably off-centre with respect to axis 212 in order to allow for thepresence of recess 218 as is seen in FIG. 8.

Inflation tubes 224 and 244 are joined at a certain distance fromballoons 210 and 230 and are preferably attached by their proximal endsto a stiffer but both flexible and hollow common component 250 with twointernal lumina (253 and 254) linked with inflation tubes 224 and 244respectively or, more specifically, the said above-mentioned secondinflation lumina of these tubes. Component 250 is, moreover, itselffitted at its proximal end (252) with two connection systems with fluidsources linked with lumina 253 and 254 respectively, allowing balloons210 and 230 to be expanded. These connection systems may, for example,be of the type known as “Luer-Lock”. A variant on this is that theabove-mentioned connection systems may be adapted to take a standardinflation syringe tip.

It is important that the above-mentioned connection systemscommunicating with, respectively, lumina 253 and 254 formed insidecomponent 250 should allow the two balloons (210 and 230) to be expandedseparately.

Balloons 210 and 230 are preferably covered prior to use with aremovable sheath (260). Sheath 260 covers the full length ofendoprosthesis 100, i.e. preferably a minimum of 15 to 20 mm. Sheath 260is preferably linked at its proximal end to a wire (262) facilitatingremoval of sheath 260 by pulling the said wire 262. Wire 262 preferablypasses through common tube 250.

Sheath 260 can, however, be omitted when the balloon system alone isused, i.e. without endoprosthesis 100.

The “Luer-Lock” connection systems shown in FIG. 12 are referred to as252. Furthermore, reference n°270 in FIG. 12 labels a schematicinflation system comprising a pressure gauge (272) adapted for linkageto one of the connection system (252) with a view to dilating one ofballoons 210 and 230.

Reference n°253 and n°254 in FIG. 13 label the two feeder lumina linkingconnection systems 252 with tubes 224 and 244 respectively. In addition,reference n°255 in FIG. 13 labels the lumen housing the wire (262)facilitating the removal of sheath 260.

In accordance with a particular embodiment that is, naturally,non-exhaustive, asymmetric double balloon 200 for coronary angioplastyconforming with this invention has the following dimensions:

guide-wires 222 and 242 are 0.036 cm (0.014 inch) guide-wires;

the longer balloon (210) is 20 to 25 mm in length, depending on themodel;

its proximal portion (219) is approximately 3.5 mm in diameter andapproximately 6.5 mmn in length after inflation;

recess 218 is approximately 3.5 mm in length;

distal portion 217 is approximately 10 mm in length and approximately 3mm in diameter after inflation;

the second balloon (230) is approximately 13 mm in length andapproximately 3 mm in diameter after inflation;

tubes 224 and 244 are joined approximately 10 mm from the proximal end(216) of balloon 210;

the lengths of the two tubes 224 and 244 between the point at which theyjoin and common component 250 may range from approximately 20 to 30 cm;

the overall length, including balloons 210 and 230 and their feedertubes is preferably approximately 135 mm;

the length of common tube 250 ranges from approximately 110 to 115 mm;and

the outer diameter of the device with balloons 210 and 230 completelydeflated preferably does not exceed 2 mm, so that the whole unitincluding the two balloons 210 and 230 and feeder tubes 224 and 244 maypass through an 8F guiding-catheter with an internal diameter of 2.6 mm.The case is the same in the version of the balloon device fitted withendoprosthesis 100 and sheath 260.

The portion of tubes 224 and 244 that is located downstream ofguide-wire exits 223 and 243, is preferably made of plastic.

The portion of tubes 224 and 244, including common portion 250, that islocated upstream of exits 223 and 243 may be made of plastic or metal.

This tube (224, 244 and 250) must be as hydrophilic as possible in orderto be able to slide inside its carrier catheter or guiding catheter.

It should be noted that balloons 210 and 230 are mutually independent.They are indirectly linked only in the area of common tube 250.

Guide-wires 222 and 242 preferably emerge from tubes 224 and 244 on thenearer side of common section 250, as is seen in FIG. 11. Exit points223 and 243 of guide-wires 222 and 242 are preferably at a slightdistance from each other and are marked differently for identification.

A description now follows of the process for installing endoprosthesis100 using asymmetric double balloon 200 in accordance with thisinvention.

Prior to use, the unit combining the two balloons (210 and 230) andbifurcated endoprosthesis 100 is protected by covering sheath 260. Thisunit fitted with sheath 260 is firstly maneuvered close to thebifurcation stenosis area. Its position is monitored using radio-opaquetracers 220 and 240.

Once the balloon (210 and 230)/endoprosthesis (100) unit has arrived atthe bifurcation, above-mentioned sheath 260 can be withdrawn by pullingwire 262.

After protective sheath 260 has been withdrawn, guide-wires 222 and 242,which have been inserted into blood vessels T2 and T3 branching off fromthe coronary bifurcation, are manipulated. Balloons 210 and 230, locatedrespectively inside proximal section 110 and distal section 120 in thecase of balloon 210 and inside distal section 140 in the case of balloon230, are still in a deflated state at this stage. Once it has beenascertained that sections 120 and 140 of the endoprosthesis have beencorrectly positioned at the bifurcation using radio-opaque tracers 220and 240 contained in the balloons, the balloons can be inflated.

To this end, the first asymmetric balloon (210), i.e. the longer balloonwhich facilitates expansion of the main structure (110) of theendoprosthesis and of section 120, aligned with it, is preferablyinflated first. Typically balloon 210 thus increases proximal portion110 of the endoprosthesis to 3.5 mm and distal portion 120 to 3 mm.

This is followed by inflation of the shorter balloon (230), whoseproximal end 236 fills recess 218 in balloon 210. Inflating balloon 230thus dilates section 140 of the endoprosthesis. The proximal taperedshape of section 140 fits into the truncated form or form with itscorner missing (115) of the main or proximal structure (110) of theendoprosthesis opposite and thus completely covers the ostial portion orbifurcation area of the coronary branching artery dilated and stented inthe course of this procedure.

Once the bifurcated endoprosthesis has been deployed and installed, asshown in FIG. 7. balloons 210 and 230 can be deflated and withdrawn.

Balloons 210 and 230 can be deflated and withdrawn simultaneously orseparately. as appropriate, after being detached from the unit.

It is advantageous for balloons 210 and 230 to be made from an elasticmaterial manufactured from a plastic polymer.

This invention is not, of course, restricted to the particularembodiment described above but stems to any and all variants consistentwith the idea embodied.

In particular, the invention is not limited to dilation of a bifurcationarea in a coronary artery showing a lesion at the bifurcation usingendoprosthesis 100 and employing dilation of balloons 210 and 230. Theinvention may also apply to other blood-vessel bifurcations, arteries orveins, such as, for example and non-limitatively, renal arteries,supra-aortic trunci, arteries leading from the aorta to the abdomen orto the low limbs, etc.

A particular variant of the invention is one in which balloon 210 mayincorporate two portions (217 and 219), distal and proximalrespectively, located on either side of recess 218 and having the samediameter.

During deployment, balloon 230 may be inflated before balloon 210.

Furthermore, installation and dilation of bifurcated endoprosthesis 100may be envisaged using systems other than the double balloon structureillustrated in FIG. 8 et seqq., and, in a corollary manner, thedouble-balloon system (200) may be used as a double balloon for coronarybifurcation lesion angioplasty not involving use of an endoprosthesis.

According to a variant of the invention, the first balloon 210 issymetric about its longitudinal axis 212. In other words the recess 218is annular and symetric of revolution about this axis 212.

What is claimed is:
 1. A balloon system for dilating blood vesselscomprising: a first balloon (210) of suitable length for beingpositioned in two approximately aligned sections (T1 and T2) for thevessel for treatment: a main stem (T1) and a branching vessel (V2),located one on each side of a bifurcation area; and a second balloon(230) suitable for positioning in a second blood vessel (T3) branchingoff from the bifurcation wherein the first balloon (210) incorporates alateral recess (218) intended for positioning opposite the bifurcationarea in order to house the proximal end (236) of the second balloon(320).
 2. A system, as claimed in claim 1, characterised by the factthat the proximal portion (219) of the first balloon (210) locatedupstream of the recess (218) is of greater diameter than the distalportion (217) of the same balloon located downstream of the recess.
 3. Asystem, as claimed in claim 1, characterised by the fact that eachballoon has a radio-opaque tracer (220 and 240).
 4. A system, as claimedin claim 1, characterised by the fact that the two balloons (210 and230) are placed in a removable sheath (260) combined with a manoeuvringwire (262).
 5. A system, as claimed in one of claim 1, characterised bythe fact that each balloon (210 and 230) has an inflation tube (224 and244) protruding from its proximal end.
 6. A system, as claimed in claim1, characterised by the fact that the two inflation tubes (224 and 244)are joined to a common component (250) comprising two lumina at acertain distance from the proximal end of the balloons (210 and 230). 7.A system, as claimed in claim 1, characterised by the fact that eachballoon (210 and 230) is combined with a guide (121 and 141).
 8. Asystem, as claimed in claim 1, characterised by the fact that the secondballoon (230) is shorter than the first balloon (210).
 9. The use of thesystem defined by claim 1 for dilation of an endoprosthesis for thetreatment of blood-vessel bifurcation stenosis at a level of abifurcation area between a main vessel stem and two secondary vesselstems having a diameter inferior to a diameter of the main vessel stemand branching off from the main vessel stem at the bifurcationcomprising three tubular sections (110, 120 and 140) and twoarticulation connectors (130 and 150): a proximal section (110) intendedfor insertion into the main vessel stem; a first distal section (120)aligned at least approximately with the proximal section (110) andintended for insertion into a first secondary blood vessel (T2)branching off from the bifurcation, the first distal section (120) beinglinked to the proximal section (110) by a lateral connector (130); and asecond distal section (140) located at the side of the first distalsection (120) and intended for insertion into a second secondary bloodvessel (T3) branching off from the bifurcation, both distal sections(120 and 140) having their proximal ends linked by a second connector(150) which allows relative pivoting of said distal sections (120 and140) about said second connector (150) to accommodate the blood-vesselbifurcation.
 10. The use of the system consistent with claim 1 forbifurcation lesion angioplasty.
 11. A balloon system for dilating bloodvessels comprising: a first balloon (210) of suitable length for beingpositioned in two approximately aligned sections (T1 and T2) for thevessel for treatment: a main stem (T1) and a branching vessel (V2),located one on each side of a bifurcation area; a second balloon (230)suitable for positioning in a second blood vessel (T3) branching offfrom the bifurcation wherein a proximal portion (219) of the firstballoon (210) located upstream of a recess (218) is of greater diameterthan a distal portion (217) of the same balloon located downstream ofthe recess.
 12. A system, as claimed in claim 11, wherein the firstballoon (210) incorporates a lateral recess (218) intended forpositioning opposite the bifurcation area in order to house a proximalend (236) of the second balloon (320).
 13. A system, as claimed in claim11, wherein each balloon has a radio-opaque tracer (220 and 240).
 14. Asystem, as claimed in claim 11, wherein the two balloons (210) and 230)are placed in a removable sheet (260) combined with a maneuvering wire(262).
 15. A system, as claimed in one of claims 11 to 14, wherein eachballoon (210 and 230) has an inflation tube (224 and 244) protrudingfrom its proximal end.
 16. A system, as claimed in claim 11, wherein thetwo inflation tubes (224 and 244) are joined to a common component (250)comprising two lumina at a certain distance form the proximal end of theballoons (210 and 230).
 17. A system, as claimed in claim 11, whereineach balloon (210 and 230) is combined with a guide (121 and 141).
 18. Asystem, as claimed in claim 11, wherein the second balloon (230) isshorter than the first balloon (210).
 19. The use of the system definedby claim 11 for dilation of an endoprosthesis for the treatment ofblood-vessel bifurcation stenosis at a level of a bifurcation areabetween a main vessel stem and two secondary vessel stems having adiameter inferior to a diameter of the main vessel stem and branchingoff from the main vessel stem at the bifurcation comprising threetubular sections (110, 120 and 140) and two articulation connectors (130and 150): a proximal section (110) intended for insertion into the mainvessel stem; a first distal section (120) aligned at least approximatelywith the proximal section (110) and intended for insertion into a firstsecondary blood vessel (T2) branching off from the bifurcation, thefirst distal section (120) being linked to the proximal section (110) bya lateral connector (130); and a second distal section (140) located atthe side of the first distal section (120) and intended for insertioninto a second secondary blood vessel (T3) branching off from thebifurcation, both distal sections (120 and 140) having their proximalends linked by a second connector (150) which allows relative pivotingof said distal sections (120 and 140) about said second connector (150)to accommodate the blood-vessel bifurcation.
 20. The use of the systemdefined by claim 11 for bifurcation lesion angioplasty.
 21. A balloonsystem for dilating blood vessels comprising: a first balloon (210) ofsuitable length for being positioned in two approximately alignedsections (T1 and T2) for the vessel for treatment: a main stem (T1) anda branching vessel (V2), located one on each side of a bifurcation area;and a second balloon (230) suitable for positioning in a second bloodvessel (T3) branching off from the bifurcation wherein the secondballoon (230) is shorter than the first balloon (210).
 22. A system, asclaimed in claim 21, wherein the first balloon (210) incorporates alateral recess (218) intended for positioning opposite the bifurcationarea in order to house a proximal end (236) of the second balloon (320).23. A system, as claimed in claim 21, wherein a proximal portion (219)of the first balloon (210) located upstream of a recess (218) is ofgreater diameter than a distal portion (217) of the same balloon locateddownstream of the recess.
 24. A system, as claimed in claim 21, whereineach balloon has a radio-opaque tracer (220 and 240).
 25. A system, asclaimed in claim 21, wherein the two balloons (210) and 230) are placedin a removable sheet (260) combined with a maneuvering wire (262).
 26. Asystem, as claimed in one of claims 21 to 25, characterized by the factthat each balloon (210 and 230) has an inflation tube (224 and 244)protruding from its proximal end.
 27. A system, as claimed in claim 21,wherein the two inflation tubes (224 and 244) are joined to a commoncomponent (250) comprising two lumina at a certain distance form theproximal end of the balloons (210 and 230).
 28. A system, as claimed inclaim 21, wherein each balloon (210 and 230) is combined with a guide(121 and 141).
 29. The use of the system defined by claim 21 fordilation of an endoprosthesis for the treatment of blood-vesselbifurcation stenosis at a level of a bifurcation area between a mainvessel stem and two secondary vessel stems having a diameter inferior toa diameter of the main vessel stem and branching off from the mainvessel stem at the bifurcation comprising three tubular sections (110,120 and 140) and two articulation connectors (130 and 150): a proximalsection (110) intended for insertion into the main vessel stem; a firstdistal section (120) aligned at least approximately with the proximalsection (110) and intended for insertion into a first secondary bloodvessel (T2) branching off from the bifurcation, the first distal section(120) being linked to the proximal section (110) by a lateral connector(130); and a second distal section (140) located at the side of thefirst distal section (120) and intended for insertion into a secondsecondary blood vessel (T3) branching off from the bifurcation, bothdistal sections (120 and 140) having their proximal ends linked by asecond connector (150) which allows relative pivoting of said distalsections (120 and 140) about said second connector (150) to accommodatethe blood-vessel bifurcation.
 30. The use of the system defined by claim21 for bifurcation lesion angioplasty.